Viral Pathogens : Classification, Biology, Diseases II Flashcards
How is the viral load determined?
β RT-PCR
What leads to AIDS?
β decline of CD4 cells
What has HIV been adapted to do?
β give a very long period of infection
How do HIV+ people die?
βopportunistic infecitons
What must viruses do to survive?
β evade immune responses
How do viruses avoid being killed by immune cells?
β they replicate inside the immune cells
What is the advantage for a virus to replicate inside immune cells?
β hides viruses from immune cells and inhibits their function
β allows other pathogens to replicated in the virus infected host
What are permissive T cells?
β T cells in which the virus can replicate
What % of T cells are permissive and non-permissive?
β 95% non-permissive
β 5% permissive
Describe what happens when HIV enters a non-permissive CD4 cell?
β the virus enters but doesnβt replicate
β there is now a foreign RNA or DNA which is sensed by the cell
β sensed by IFI16 DNA sensor
β IFI16 activates the immune response
β Inflammasome response which activates caspase-1 and pyroptosis occurs
β cell death and excretion of all the inflammatory factors
β this warns other cells that there is some type of infection
What three viral proteins are involved in evading the immune response to virus replication?
β VPR
β VIF
β NEF
In permissive cells what is activated when there is foreign DNA in the cell?
β caspase-3 is activated which is a mediator of apoptosis
Describe how the cycle of immune exhaustion occurs?
1) HIV infection
2) death via pyroptosis and the release of pro-inflammatory cytokines and cellular contents occur
3) Inflammation occurs which is good for the virus because it brings more healthy CD4 cells that allows the virus to infect new cells
4) the inflammatory state hyper charges the immune system so much that there is migration of the immune neutrophils and monocytes into the infected area
5) more inflammation occurs and the exhaustion of the immune system occurs
What are 2 viruses associated with HIV?
β HSV
β Kaposiβs sarcoma herpesvirus
What are 2 bacteria associated with HIV?
β mycobacterium tuberculosis
β salmonella